We report the results of ex vivo studies of different types of human tissue (colon, uterine cervix, brain) with the custom-built multi-wavelength wide-field imaging Mueller polarimeter for medical diagnostics. Any type of pathology has impact on tissue microstructure at the very early stage of disease development. Consequently, it modifies optical properties of tissue. Apart from changing the scattering of light by tissue, disease progression also leads to the loss of tissue linear birefringence by breaking its fine fabric and erasing optical anisotropy. These structural changes can be detected early with polarized light by estimating the degree of depolarization of backscattered light, as well as the retardance of non-depolarized fraction of backscattered probing light beam. We demonstrate that polarization (scalar retardance and azimuth of optical axis) and depolarization parameters can serve as the optical markers of tissue pathology.
|